How to minimize sanding time.

[AnakinSkywalker]

I started this thread because I want to discuss with the community the best way to avoid sanding while still getting a quality product, because we all hate sanding.
I'm going to list several ways to lower the amount of time one will spend sanding, if other people have stuff to add feel free.

• Better Quality prints, depending on your printer or how fine tuned it is, you can minimize sanding by producing quality prints.
• Slowing down the print speed can improve the print at the cost of time, if you have the time try slowing it down so you can save yourself time later.
• jewelry UV resin, the thick ness of it makes it less runny than other UV resins and using a foam brush distributes it evenly allowing for a smooth surface on your print and it requires minimal preparation if the print is already a decent quality.
• Rustoleum filler primer can fill in gaps and save you time sanding by just using sheer volume to overcome the prints ridges.

I'm sure there are more that ill remember later and ill add them when i remember, with all these methods you still have to sand but you can greatly reduce the time you would be sanding by using these methods.

 

[spartan114x]

I started this thread because I want to discuss with the community the best way to avoid sanding while still getting a quality product, because we all hate sanding.
I'm going to list several ways to lower the amount of time one will spend sanding, if other people have stuff to add feel free.

• Better Quality prints, depending on your printer or how fine tuned it is, you can minimize sanding by producing quality prints.
• Slowing down the print speed can improve the print at the cost of time, if you have the time try slowing it down so you can save yourself time later.
• jewelry UV resin, the thick ness of it makes it less runny than other UV resins and using a foam brush distributes it evenly allowing for a smooth surface on your print and it requires minimal preparation if the print is already a decent quality.
• Rustoleum filler primer can fill in gaps and save you time sanding by just using sheer volume to overcome the prints ridges.

I'm sure there are more that ill remember later and ill add them when i remember, with all these methods you still have to sand but you can greatly reduce the time you would be sanding by using these methods.

Great tip about print speed. I’m a complete noob to printing so I’ll keep that in mind. Especially with no time pressure.

 

[Kahn 319]

Don't forget to think about support placement, it can cause a mess if you put them in a bad spot, try to find a flat spot to balance it on if possible. also make sure your support settings are dialed in as well, sometimes if the support is too close to the print it can cause ugly lines or gaps.

 

[ColonelPanic]

Don't forget to think about support placement, it can cause a mess if you put them in a bad spot, try to find a flat spot to balance it on if possible. also make sure your support settings are dialed in as well, sometimes if the support is too close to the print it can cause ugly lines or gaps.

Tagging on the Supports, Normal Supports will give you a better print than Tree Supports because it supports the entire part to prevent layer shifting. It does use more filament and takes more time, but in my recent experience with both methods, It's worth it. Tree really only works well for .20-.16 mm layer height prints

 

[ColonelPanic]

If you do have to sand, use a powered tool like a palm sander or belt sander with a 100 Grit sandpaper. Sanding the inside of parts will be tough, but a manual job with a low grit (80-50) can help speed it up

 

[Kahn 319]

How i usually go about it is start with the electric sander, hit the big spots, then hand sant at 120 then 240 then 400, and filler primer inbetween

 

[SgtSaint]

I'm in the same camp as Kahn 319 described with a workflow of just sanding and maybe spot putty.
I know several YouTubes have made it very popular to coat the entire print with something... bondo, resin, thinned wood filler, blah, blah, blah. And if that works for someone then cool. I'm in favor of whatever works for you.

Me - personally - one guy - I don't add a thin shell of another material to my prints. To my way of thinking: Thin layers of nearly anything have two fatal flaws: 1. They're thin making them easier to crack. Torque a part or wack it a little too hard showing off at the con and these mixtures have no flex to them. 2. I'm not confident in their adhesion properties. Maybe they're great if you do it right but I'm not comfortable with the risk of a thin coat of something not truly deeply bonding with my print but instead kinda-sorta acting like a shell top of: Like hard chocolate on ice cream. Again, that's me. And not saying anything that someone does is wrong. Its not wrong if it works for you.

I'm all about "more robot time = better print = less human" labor. Again, just one guy sharing what he does, not telling anyone what to do - For me I find all that effort to avoid work is more work than the original sanding work.

 

[AnakinSkywalker]

I'm in the same camp as Kahn 319 described with a workflow of just sanding and maybe spot putty.
I know several YouTubes have made it very popular to coat the entire print with something... bondo, resin, thinned wood filler, blah, blah, blah. And if that works for someone then cool. I'm in favor of whatever works for you.

Me - personally - one guy - I don't add a thin shell of another material to my prints. To my way of thinking: Thin layers of nearly anything have two fatal flaws: 1. They're thin making them easier to crack. Torque a part or wack it a little too hard showing off at the con and these mixtures have no flex to them. 2. I'm not confident in their adhesion properties. Maybe they're great if you do it right but I'm not comfortable with the risk of a thin coat of something not truly deeply bonding with my print but instead kinda-sorta acting like a shell top of: Like hard chocolate on ice cream. Again, that's me. And not saying anything that someone does is wrong. Its not wrong if it works for you.

I'm all about "more robot time = better print = less human" labor. Again, just one guy sharing what he does, not telling anyone what to do - For me I find all that effort to avoid work is more work than the original sanding work.

View attachment 345728

Fair enough, probably allows for your suit to be lighter as well, which is a huge plus.

 

[BHE Photos]

I'll toss my hat in the ring for the pro-resin side. When I started doing Cosplay prints (Mando armor) I used watered down wood filler and I've dabbled with bondo to fill layer lines, but once I made the switch to UV Resin I haven't used anything else. Especially since I prefer the "give hot glue guns a run for their money" approach of using a 0.8 or 1.0 mm nozzle and printing at 0.4 mm layers, I need some fairly aggressive filling.

If you already have a resin printer and all the necessary PPE, smoothing with UV Resin is super easy. What I like about it is that it's easily the fastest option. I can take a raw print of a helmet out to my garage and have the first coat of filler primer on in about 30-45 minutes. The resin cures (basically) instantly when hit with the UV light, so as soon as I'm done applying/curing, I can move right into sanding, with no concern for dry time. Also it's easy to wet sand, unlike bondo.

I also like that resin can be structural while being easy to apply. I had a helmet that I printed upside down and the supports ended up leaving a hole at the top of the helmet where it touched the build plate. I used tape on the inside to create a boundary and just poured the resin into the hole (about the size of a nickel). While bondo could have worked for that as well, the resin was a lot easier to work with.

Back to the more specific purpose of minimizing sanding, I find that for parts that won't be inspected much (elbows, knees and toes, knees and toes, etc), I can do two light coats of resin, one wet sanding pass with either 180 or 220 grit, and then move straight into priming and painting and get a satisfactory finish.

I have had some issues with delamination, though it's rare. My Star Wars Praetorian Guard helmet has a spot where I attempted to fix a layer shift and ended up with some pooled resin. You have to be careful with edges/corners. Overall though, it's still worth it to me. I also like the idea that there's a layer of UV resin over the PLA. I think of it as a composite, probably keeping the parts from warping. I have no idea what kind of temperature resistance the resin I use has though, so that's entirely anecdotal, and here in Wisconsin it's not really a big deal either way.

 

[FalseShepherd]

I really wanna try the uv resin approach.

One thing I have recently tried is mixing bondo with acetone to make a slurry. It goes on smoother than just regular bondo but is easy to sand. I always felt like bondo leaves imperfections that require spot putty but I'm not sure that's going to be the case with this slurry. Although to be honest, I haven't had time to actually start sanding it yet so I don't really know. It's a fairly large piece and the filler primer/spot putty method was taking way too long.